What comes to mind? Sights, sounds, and scents?
I would imagine that these things would vary from person to person. I find that when posed with a possible outing with friends, I go through what we might do throughout the event. This planning creates expectations in my mind the, in the past, I have had to overcome disappointment at expectations not being met. These are considered negative interpersonal communications, from my perspective.
From planning to problem solving, internal conflict resolution, and evaluations and judgments of self and others, we communicate with ourselves through intrapersonal communication.
As a person with, what I believe, is a strong sense of self, I struggle occasionally when I experience anxiety related to external conflict and problem solving. This interpersonal communication going on in my head, and I'm sure others, can sometimes fight each other for dominance.